Upside Down Rhubarb Cake

It's spring in northern New York and the rhubarb is plentiful!!! My friend Donna brought me some of the smallest, sweetest rhubarb I have ever had. I came across this recipe and decided to give it a try and after having a piece, I think this is my new favorite rhubarb recipe!!!!

Crumb topping:
4 Tbsp. butter, melted then add
1/2 cup flour
1/4 cup sugar
dash of salt
Combine until crumbly... set aside

Butter a 9 inch round cake pan, then cut up  4 Tbsp. of butter and place them all over the bottom of the cake pan.

In bowl, combine 3 cups rhubarb, sliced into 1/2 inch pieces
and 3/4 cup sugar.
Let stand a few minutes.

In another bowl combine
1 stick of butter, softened
1 cup sugar
with electric mixer until  it is pale and fluffy then add
1/2 tsp orange zest
1 Tbsp. orange juice.
When combined add
2 eggs, one at a time
Then mix in:
 1 1/2 cups flour
1 1/2 tsp. baking powder
dash salt
When that mixture is well incorporated fold in
1 cup sour cream
until it is well combined.

Put the rhubarb mix on top of the butter in the cake pan. Carefully spread the cake batter over top. Then sprinkle the crumb topping on last.
Bake at 350  about an hour till the center tests clean with a toothpick. 

 Let cool for ten minutes then invert on a wire rack to cool.